Efficient multi-zone multi-velocity hvac control method and apparatus

ABSTRACT

The present invention provides heating and cooling conditioning control in a multiple zone HVAC system to achieve enhanced user comfort and energy efficiency. In particular, the present invention provides a multiple zone HVAC control apparatus that senses and responds to changes in duct air pressure in order to prevent undesirable zone conditioning, energy loss, and register noise. The present invention offers particular benefit in high and medium velocity HVAC environments which typically suffer from pronounced deficiencies when zone demands diverge. Due to its ability to respond to changes in duct pressure, the present invention permits the conditioning of an increased number of zones without degradation in performance or user comfort. Additionally, the present invention provides a means to control elements within a multiple zone HVAC system including but not limited to heating and cooling sources, air circulator fans, zone dampers, and circulating pumps to achieve desired zone conditioning.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention generally relates to control systems used toregulate heating and cooling in HVAC systems. Specifically, the presentinvention relates to methods and apparatus employed to control thetemperature and flow of forced air through duct systems for theregulation of indoor climate. The application of the present inventionfor the regulation of indoor temperature is appropriate where a forcedair heating or cooling source is available to provide air flow through aduct system. This invention finds particular application where theforced air duct system is divided into zones each requiring discretecomfort conditioning, employs high or medium velocity small diameterducts, and where increased efficiency and reduced noise in the deliveryof said conditioning is desirable.

2. Description of the Prior Art

Prior art embodiments of HVAC control systems are generally capable ofswitching heating and cooling sources on and off while increasing ordecreasing air circulator fan speed through 2 to 3 steps typically,occasionally more, in order to achieve desired indoor conditioning asdemanded by a user programmed thermostat. Multiple zone versions of theabove are available wherein each zone is equipped with a thermostat inorder to achieve isolated conditioning. Dampers are typically used tocontrol the flow of temperature conditioned air to each zone in themultiple zone system. When conditioning demands diverge between zones ina prior art multiple zone system, the dampers are used to partiallyclose off those zones deemed by the system to require reduced air flow.The system is unable to fully close dampers due to the need to retainthe ability to vent excess air in the system. As a result, undesirableconditioning may be delivered to zones which do not demand it. Due tothe reduction in the capacity of the duct system to process excess airflow upon the partial closure of one or more dampers, the air pressurein the system increases, often dramatically. The increased pressure inthe duct system subsequently increases the rate of air flow through theremaining open dampers causing significantly undesirable conditioningperformance and noise at registers. These deficiencies are particularlypronounced in high and medium velocity small diameter duct systems whichare increasingly incorporated in new home constructions. The number ofzones in such systems is limited due to the amplification of thedeficiencies with the addition of each zone. Further, there is asignificant drop in the overall energy efficiency of the multiple zoneheating and cooling system when undesirable conditioning and noise arepresent.

SUMMARY OF THE INVENTION

The present invention provides a multiple zone heating and coolingcontrol system and method wherein undesirable conditioning due to damperoperation is reduced or eliminated and noise due to higher pressure airflow is significantly attenuated. In particular, the present inventionprovides a means to monitor changes in pressure due to damper operationand air circulator fan speed and to reactively adjust air circulator fanspeed in order to maintain a desirable static pressure. Unlike prior artembodiments and due to its ability to maintain a desirable staticpressure, the present invention permits the full closure of zone dampersas required by the operation of the multiple zone HVAC system. Thereby,this invention is able to provide significantly greater user comfort andenergy efficiency, particularly in higher pressure high and mediumvelocity HVAC systems, permitting an increase in the number of zoneswhile delivering performance generally free of the deficiencies of theprior art.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic diagram of the implementation of an embodiment ofan efficient multiple zone and multiple velocity HVAC control apparatuswithin an HVAC system.

FIG. 2 is a block diagram illustrating the internal components of anembodiment of an efficient multiple zone and multiple velocity HVACcontrol apparatus.

FIG. 3 is a block diagram illustrating the internal components of anembodiment of an efficient multiple zone and multiple velocity HVACcontrol apparatus with additional features.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In order to better understand the embodiment of the present invention,an embodiment of an efficient multiple zone and multiple velocity HVACcontrol method and apparatus will be described with reference to FIGS.1, 2, and 3. An embodiment of an implementation of an efficient multiplezone and multiple velocity HVAC control apparatus within an HVAC systemis provided as in FIG. 1 comprised of a heating and/or cooling source 5,an air circulator fan with variable speed motor 7, a duct network 25 todirect airflow as illustrated by arrow 27, a pressure sensor 29,motorized dampers 9, 11, 13 and 15 servicing zones 1, 2, 3, and 4respectively, thermostats 17, 19, 21, and 23, and controller board 31.Operation of said HVAC system is initiated by input from thermostats 17,19, 21, and 23 providing real-time temperature and user desiredtemperature input to the controller board 31. Further data such as thestatic pressure in the duct network 25 is provided to the controllerboard 31 which in turn controls the operation of the heating and/orcooling source 5, the air circulator fan 7, and each of the motorizeddampers 9, 11, 13 and 15 to condition each zone to achieve the closestapproximations of the user desired temperatures as provided bythermostats 17, 19, 21, and 23 in zones 1, 2, 3, and 4 respectively.Zone 4, labeled ZONE N, in FIG. 1 is provided to illustrate that thenumber of zones is not limited by the capacity of the efficient multiplezone and multiple velocity HVAC control apparatus but by theconfiguration and intended application of the HVAC system. It isunderstood that the system could be equipped with a fifth, sixth,seventh, or more zones each equipped with dampers and thermostats tosatisfy application requirements and each provided with similar zoneconditioning as above without departing from the spirit of the presentinvention. It is further understood that the implementation of pressuresensing in the duct network 25 as provided by pressure sensor 29providing pressure data to the controller board 31 for enhancedoperation and performance of an HVAC system finds particular applicationin high and medium velocity small diameter duct environments but may bebeneficially applied in low pressure low velocity systems withoutdeparting from the spirit of the present invention.

To provide greater understanding of the present invention, an embodimentof the efficient multiple zone and multiple velocity HVAC controlapparatus is provided as in FIG. 2. A multiple zone HVAC controllerboard 37 is shown comprising a source control element 49, a fan controlelement 51, a damper control element 39, a pressure sensor input element41, a thermostat input element 43, a power supply unit 45, and acontroller processor element 47. Said source control element 49 providesthe facility to switch a heating and/or a cooling source on and off asrequired by the conditioning demands of the user of an HVAC system. Saidfan control element 51 provides a signal to an air circulator fan toincrease or decrease fan speed thereby increasing or decreasing air flowin a duct network. Said fan control signal is a variable type such aspulse width modulated, 0-10V, or other proportional control schemethereby providing a level of fan speed control range and granularityunattainable by typical step speed control means. Said damper controlelement 39 provides the facility to incrementally open or close or tofully open or close each motorized zone damper in a multiple zone HVACsystem according to the independent requirements of each zone. Saidpressure sensor input element 41 provides pressure sensor datarepresenting the air pressure in the duct network of an HVAC system tothe controller processor element 47 which in turn sends signals to fancontrol element 51 to adjust air circulator fan speed to maintain adesired static pressure as required. Said thermostat input element 43provides real-time and user desired temperature data for each zone in amultiple zone HVAC system to said controller processor element 47 whichin turn may adjust the elements of the HVAC system controlled by andthrough source control element 49, fan control element 51, and dampercontrol element 39 in order to achieve the desired zone conditioningdemanded by the user. Said power supply unit 45 provides sufficientvoltage and current to the controller processor element 47 as requiredby the application and to allow said controller processor element 47 tosend the necessary signals to the conditioning elements of the systemincluding said source control element 49, fan control element 51, anddamper control element 39. Said power supply unit 45 may or may not bephysically implemented on the multiple zone HVAC controller board 37 andis shown simply to illustrate that said controller board 37 requires apower source. Generally, building HVAC systems provide a 24 VAC powersource for the implementation of standard controller boards and suchpower sources would be sufficient for the power supply requirements ofthe present invention. Operation of the multiple zone and multiplevelocity HVAC control apparatus by other power supply means sufficientto support its power requirements would not depart from the spirit ofthe present invention.

The specific adjustments made to fan speed, damper angle, and sourceselection by the multiple zone and multiple velocity HVAC controlapparatus are made in response to input data provided by the thermostatinput element 43 and the pressure sensor element 41 and are guided bythe heating and cooling strategy as programmed by a technician into thecontroller processor element 47 typically at the time of installation ofthe apparatus. Said heating and cooling strategy is generally specificto the capacity, geometry, features, and application of the HVAC systemand is further influenced by end user requirements and the climate inthe region of application.

To provide greater understanding of the versatility of the presentinvention, another embodiment of the efficient multiple zone andmultiple velocity HVAC control apparatus with additional features isprovided as in FIG. 3. A multiple zone HVAC controller board 53 is showncomprising a source control element 69, a fan control element 71, adamper control element 55, a pressure sensor input element 57, athermostat input element 59, a power supply unit 61, a pump controlelement 63, a building automation input element 65, and a controllerprocessor element 67. Said source control element 69, fan controlelement 71, damper control element 55, pressure sensor input element 57,thermostat input element 59, and said power supply unit 61 providesimilar functionality within the system as those same elements presentin and as previously described with reference to FIG. 2. However, inthis embodiment, an additional control element is provided in the formof said pump control element 63 which provides a signal to a variablespeed circulating pump element in an HVAC system to modulate its speedin response to the conditioning requirements system. Also, an additionalinput source is provided in the form of said building automation inputelement 65 which provides data to said controller processor element 67.Said controller processor 67 uses data provided by said buildingautomation input element 65 in conjunction with data provided by saidpressure sensor input element 57 and said thermostat input element 59 tosend signals to make adjustments to HVAC system elements controlled bysaid source control element 69, said fan control element 71, said dampercontrol element 55, and said pump control element 63 as guided by aheating and cooling strategy to achieve optimum zone conditioning in amultiple zone HVAC system.

For an HVAC system embodiment based on the embodiment of the efficientmultiple zone and multiple velocity HVAC control apparatus withadditional features as provided in FIG. 3, the specific adjustments madeto fan speed, damper angle, circulating pump speed, and source selectionby the multiple zone and multiple velocity HVAC control apparatus aremade in response to input data provided by the thermostat input element59, the pressure sensor input element 57, and the building automationinput element 65 and are guided by the heating and cooling strategy asprogrammed by a technician into the controller processor element 67typically at the time of installation of the apparatus. Said heating andcooling strategy is generally specific to the capacity, features,geometry, and application of the HVAC system and is further influencedby end user requirements and the climate in the region of application.

I claim as my invention:
 1. An efficient multiple zone and multiplevelocity HVAC control apparatus comprising: (a) a source controlelement; (b) a fan control element; (c) a damper control element; (d) apressure sensor element; (e) a thermostat input element; (f) acontroller processor; (g) a power source.
 2. An efficient multiple zoneand multiple velocity HVAC control apparatus as in claim 1, wherein saidsource control element can switch a heating or cooling source on or offas required by the operation of an HVAC system.
 3. An efficient multiplezone and multiple velocity HVAC control apparatus as in claim 1, whereinsaid fan control element can control the speed of an air circulator fanas required by the operation of an HVAC system.
 4. An efficient multiplezone and multiple velocity HVAC control apparatus as in claim 3, whereinsaid fan control element uses a variable type signal such as a pulsewidth modulated or other proportional control scheme signal to controlthe speed of an air circulator fan.
 5. An efficient multiple zone andmultiple velocity HVAC control apparatus as in claim 1, wherein saiddamper control element facilitates the opening or closing of damperspermitting or restricting airflow to zones as required by the operationof a multiple zone HVAC system.
 6. An efficient multiple zone andmultiple velocity HVAC control apparatus as in claim 5, wherein saiddamper control element facilitates the incremental adjustment of damperangles to provide precision air flow regulation as required to zones ina multiple zone HVAC system.
 7. An efficient multiple zone and multiplevelocity HVAC control apparatus as in claim 1, wherein said pressuresensor element provides duct network air pressure data to saidcontroller processor.
 8. An efficient multiple zone and multiplevelocity HVAC control apparatus as in claim 1, wherein said controllerprocessor uses duct network air pressure data provided by said airpressure sensor element to identify deviations from a predefined optimalstatic air pressure level.
 9. An efficient multiple zone and multiplevelocity HVAC control apparatus as in claim 1, wherein said controllerprocessor sends signals to said fan control element to increase ordecrease fan speed in response to duct network air pressure data inorder to correct deviations from a predefined static air pressure levelfor the optimal operation and performance of an HVAC system.
 10. Anefficient multiple zone and multiple velocity HVAC control apparatus asin claim 1, wherein said thermostat input element provides zonetemperature data and user desired zone conditioning data to saidcontroller processor.
 11. An efficient multiple zone and multiplevelocity HVAC control apparatus as in claim 1, wherein said controllerprocessor uses zone temperature data provided by said thermostat inputelement to determine actions required to achieve user desired zoneconditioning.
 12. An efficient multiple zone and multiple velocity HVACcontrol apparatus as in claim 1, wherein said controller processor sendssignals to any or all of said source control element, fan controlelement, and damper control element in response to temperature dataprovided by said thermostat input element in order to achieve userdesired zone conditioning.
 13. An efficient multiple zone and multiplevelocity HVAC control apparatus as in claim 1, wherein said power sourceprovides electrical power to the component elements of the controlapparatus and is sufficient to allow said component elements to sendcontrol signals to components of an HVAC system for the optimaloperation and performance thereof.
 14. An efficient multiple zone andmultiple velocity HVAC control apparatus as in claim 1, wherein saidcontroller processor may also be configured to receive and act on dataprovided to it by building automation elements in an HVAC system.
 15. Anefficient multiple zone and multiple velocity HVAC control apparatus asin claim 1, wherein said controller processor may also be configured tosend signals to a pump controller which in turn modulates the speed of acirculating pump in an HVAC system to achieve user desired zoneconditioning.
 16. An efficient multiple zone and multiple velocity HVACcontrol apparatus as in claim 1, wherein said controller processor isreadily programmable by an HVAC technician to set the number of zones,the primary zone, the optimal static duct pressure, and the heating andcooling strategy.
 17. An efficient multiple zone and multiple velocityHVAC control apparatus as in claim 1, wherein said apparatus may beimplemented in either high velocity, medium velocity, or low velocityHVAC environments.
 18. An efficient multiple zone and multiple velocityHVAC control method comprising: (a) a primary zone element; (b) aheating and cooling strategy.
 19. An efficient multiple zone andmultiple velocity HVAC control method as in claim 18, wherein a primaryzone is selected by an installation technician and said primary zoneelement determines whether an HVAC system is in a heating or coolingmode of operation.
 20. An efficient multiple zone and multiple velocityHVAC control method as in claim 18, wherein said heating and coolingstrategy is programmed into a multiple zone HVAC control apparatus andsaid strategy is typically determined by the capacity, features,geometry, and specific application of an HVAC system and furtherdetermined by the requirements of the user and climactic factors in theregion of application.